For the production of certain mouldings from work materials on a rubber basis use is made of separately produced unvulcanised half-finished parts or parisons. In this connection here we are speaking more particularly of so-called Apex rings, which are further employed in the finishing of vehicle tires for the formation of a steel bead at the edge side. These pre-finished parisons or half-finished mouldings are produced in corresponding moulds without vulcanisation as "accelerated rubber mixtures". During the further working parisons are vulcanised with the work material for the other part of the final moulding introduced into a corresponding mould and thereby integrated with the final moulding.
Particular requirements are placed upon the external shape as well as the technological qualities of the above-mentioned moulded parisons of rubber mixtures. The parisons must be worked very exactly and must possess particular qualities in respect of the material characteristics such as plasticity and stability of the external surface of the parison.